Abstract LB-405: Modulation of the metabolism of air-borne pollutants by broccoli sprout beverages: Results of a short term, cross-over clinical trial in Qidong, People's Republic of China

Abstract

Abstract Epidemiological evidence has suggested that consumption of a diet rich in cruciferous vegetables reduces the risk of several types of cancers and chronic degenerative diseases. In particular, broccoli sprouts are a convenient and rich source of the glucosinolate, glucoraphanin (GR) which can release the chemopreventive agent, sulforaphane (SF), an inducer of glutathione transferases. Two broccoli sprout-derived beverages, one glucoraphanin-rich (GRR) and the other sulforaphane-rich (SFR), were evaluated for SF bioavailability, tolerability and pharmacodynamic action. The GRR beverage relied on the conversion of GR to SF in the gut microflora whereas the SFR beverage was prepared by conversion of GR to SF with myrosinase from daikon sprouts prior to consumption. Study participants were recruited from the farming community of He Zuo Township, Qidong, People's Republic of China, previously documented to have a high incidence of hepatocellular carcinoma and more recently, exposures to substantive levels of air-borne pollutants including phenanthrene, acrolein, crotonaldehyde, benzene and ethylene oxide. Two hundred five individuals were screened at village clinics and 50 willing, healthy participants were randomized into two treatment arms. The study protocol was as follows: a 5-day run-in period, a 7-day administration of beverages, a 5-day washout period, and a 7-day administration of the opposite beverage. Bioavailability of SF, as indicated by excretion of GR, SF and SF-thiol conjugates in urine collected daily 12 hours after dosing, was measured by isotope dilution mass spectrometry. The urinary excretions of SF and its thiols were substantially greater in individuals receiving a SFR beverage compared to a GRR beverage. Determination of possible pharmacodynamic action of the SFR and GRR beverages has been assessed through measures of the urinary excretion of the mercapturic acids of acrolein, crotonaldehyde, ethylene oxide, benzene and 1,3-butadiene using liquid and gas chromatography coupled to mass spectrometry. Statistically significant increases in the levels of excretion of glutathione-derived conjugates of acrolein, crotonaldehyde, and benzene were seen in individuals receiving SFR, GRR or both compared to their pre-intervention baseline values. Increases provoked by SFR were greater than for GRR, but the differences were not significantly different. Thus, chemopreventive intervention may attenuate risks to health associated with exposures to air-borne pollutants in addition to possible effects on aflatoxin exposures in this region. Supported by NIEHS grant P01 ES006052. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-405. doi:10.1158/1538-7445.AM2011-LB-405